Elimination of an opacified crystal lens through an ultrasonic emulsification and implantation of a lens into an eye that has undergone the elimination of the crystal lens are commonly carried out in cataract surgeries. Nowadays, a soft intraocular lens made of a soft material, such as a silicon elastomer or a soft acrylic material, is used, an optical part of the intraocular lens is folded by an intraocular lens insertion device, and the intraocular lens in this state is pushed by a plunger to push out the lens from a nozzle, and is inserted into an eye through an incision which is smaller than the diameter of the optical part.
Intraocular lens insertion devices can insert an intraocular lens into an eye through a tiny incision, thereby reducing the possibilities of a corneal astigmatism or an infection disease after a surgery. To further reduce the possibility of a corneal astigmatism or an infection disease after a surgery, it is desirable to minimize an incision for inserting an intraocular lens into an eye as much as possible.
To minimize an incision, however, it is necessary to fold an intraocular lens in a smaller size with the miniaturization of the incision. Folding an intraocular lens in a smaller size increases elastic restoring force of the intraocular lens, so that a slide resistance applied to a plunger becomes large in pushing out the intraocular lens from a nozzle by the plunger.
When the slide resistance applied to the plunger becomes large on some level, the leading end of the plunger may run on the face of the optical part of the intraocular lens. Accordingly, even if the intraocular lens is inserted into an eye, the intraocular lens may be damaged by the leading end of the plunger, so that it is difficult in some cases to obtain a desired property of the intraocular lens appropriately.
To overcome such a problem, there is disclosed an intraocular lens insertion device which captures an intraocular lens disposed on a lens disposing part without no load by a plunger having a slot formed at the leading end thereof from a position parallel to the intraocular lens, and prevents the plunger from running on the intraocular lens when releasing the intraocular lens (for example, in Patent Document 1).
Further, there is also disclosed another intraocular lens insertion device having a circular nose part, offset asymmetrically with respect to the central line of a cartridge lumen, and provided at the leading end of a plunger (for example, in Patent Document 1). According to this intraocular lens insertion device, the plunger is urged in such a way that the nose part is pressed against the lower part of the cartridge lumen, and is caused to slide the lower part of the cartridge lumen by such urging force, thereby preventing the nose part from running on an intraocular lens.
Patent Document 1: Japanese Un-Examined Patent Application Publication No. H9-506285
Patent Document 2: Japanese Un-Examined Patent Application Publication No. 2002-516709